.\" -*- nroff -*-
.\" Copyright 2009-2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" Copyright (c) 2020      Google, LLC. All rights reserved.
.\" $COPYRIGHT$
.TH MPI_Comm_create_errhandler 3 "#OMPI_DATE#" "#PACKAGE_VERSION#" "#PACKAGE_NAME#"
.SH NAME
\fBMPI_Comm_create_errhandler \fP \- Creates an error handler that can be attached to communicators.

.SH SYNTAX
.ft R
.SH C Syntax
.nf
#include <mpi.h>
int MPI_Comm_create_errhandler(MPI_Comm_errhandler_function \fI*function\fP,
	MPI_Errhandler *\fIerrhandler\fP)

.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_CREATE_ERRHANDLER(\fIFUNCTION, ERRHANDLER, IERROR\fP)
	EXTERNAL	\fIFUNCTION\fP
	INTEGER	\fIERRHANDLER, IERROR\fP

.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_Comm_create_errhandler(\fIcomm_errhandler_fn\fP, \fIerrhandler\fP, \fIierror\fP)
	PROCEDURE(MPI_Comm_errhandler_function) :: \fIcomm_errhandler_fn\fP
	TYPE(MPI_Errhandler), INTENT(OUT) :: \fIerrhandler\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH DEPRECATED TYPE NAME NOTE
.ft R
MPI-2.2 deprecated the MPI_Comm_errhandler_fn and
MPI::Comm::Errhandler_fn types in favor of
MPI_Comm_errhandler_function and MPI::Comm::Errhandler_function,
respectively.  Open MPI supports both names (indeed, the _fn names are
typedefs to the _function names).

.SH INPUT PARAMETER
.ft R
.TP 1i
function
User-defined error handling procedure (function).

.SH OUTPUT PARAMETERS
.ft R
.TP 1i
errhandler
MPI error handler (handle).
.ft R
.TP 1i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
MPI_Comm_create_errhandler creates an error handler that can be attached to communicators. This function is identical to MPI_Errhandler_create, the use of which is deprecated.
.sp
In C, the user routine should be a function of type MPI_Comm_errhandler_function, which is defined as
.sp
.nf
    typedef void MPI_Comm_errhandler_function(MPI_Comm *, int *, \&...);
.fi
.sp
The first argument is the communicator in use. The second is the error code
to be returned by the MPI routine that raised the error. This typedef replaces MPI_Handler_function, the use of which is deprecated.
.sp
In Fortran, the user routine should be of this form:
.sp
.nf
    SUBROUTINE COMM_ERRHANDLER_FUNCTION(COMM, ERROR_CODE, \&...)
        INTEGER COMM, ERROR_CODE
.fi

.SH ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
.sp
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.



